摘要:

For good reasons, there has been a spate of articles, much thinking, and a fair amount of industrial action on making chemicals and fuels from methanol, Only methane and methanol are made commercially in over 99% yields from synthesis gas.

ISSN:0161-4940    

DOI:10.1080/01614948408064715

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Light olefins will play a dominant role in any future methanol-based chemicals economy. Olefins are initial products in the conversion of methanol to hydrocarbons over zeolite catalysts [1]. The overall reaction path may be represented by

ISSN:0161-4940    

DOI:10.1080/01614948408064716

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Over the past 35 years, the chemical industry has largely changed its raw material base from coal to petroleum and natural gas. This has basically meant a shift from acetylene chemistry and coal tar chemistry to olefin chemistry (ethylene, propylene, isobutylene and butadiene) and petroleum-derived benzene, toluene, and xylenes. Methanol, ammonia, and hydrogen are still made from synthesis gas. However, synthesis gas is now made by methane reforming instead of coal gasification. These conversions have involved a vast expenditure of money, time, and effort, but the financial incentives have been huge and a great deal of new chemistry has been uncovered.

ISSN:0161-4940    

DOI:10.1080/01614948408064717

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Hydroprocessing catalysts based upon the transition metal sulfides have been widely used for over 60 years and catalysts such as Co/Mo/Al2O3remain the industry “workhorses” in hydroprocessing of petroleum-based feedstocks [1]. Such applications include sulfur removal (hydrodesulfurization), nitrogen removal (hydrogenitrogenation), and product quality improvement (hydrotreating, hydroconversion). Original interest (prior to World War II) in these catalysts centered on their activityin the hydrogenation of coal liquids which contain considerable amounts of sulfur, thus maintaining the transition metal in the sulfided state. It was quickly discovered that Co, Ni, Mo, and W sulfides and their mixtures were the most active and least expensive of the transition metal sulfides [2]. Later (post-World War II) their major uses shifted to hydroprocessing of sulfur- and nitrogen-containing petroleum-based feedstocks with Co- and Ni-promoted Mo and W catalysts usually supported on Al2O3. However, as petroleum feedstock supplies dwindle, we are required to process larger quantities of “dirtier” feeds containing larger amounts of sulfur, nitrogen, and metals. In order to meet these requirements in the future, a new generation of transition metal sulfidebased catalysts will be needed which have higher activities, greater selectivity to desired products, and greater resistance to poisons.

ISSN:0161-4940    

DOI:10.1080/01614948408064718

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The great current interest in hydrodesulfurization (HDS) and other hydrotreating reactions is related to the need for efficient upgrading of crude oil fractions or coal-derived liquids. The catalysts used for such reactions generally consist of molybdenum (or tungsten) supported on high surface area aluminas with cobalt or nickel added as promoters. Great efforts have been devoted to the understanding of the structural and chemical form in which the different elements are present in the active catalyst and to the establishment of correlations between such information and the various catalytic functions. This massive research effort has given valuable information on many aspects of such catalyst systems (for recent reviews of the extensive literature, see, e.g., Refs. 1–11). However, it has not been possible to reach general agreement on the types of structures present in the active catalysts and the origin of promotion

ISSN:0161-4940    

DOI:10.1080/01614948408064719

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Many industrialized western countries depend on imported foreign crude. In 1977, for example, the United States imported 46% of its oil and petroleum products, chiefly from Saudi Arabia, Iran, and other OPEC nations. By September 1, 1983, the United States imported only 28% of its oil. The chief suppliers were Mexico, with 826,000 barrels per day, Canada, with 479,000, and Venezuela, with 419,000. Saudi Arabia is now seventh on the list of suppliers for the United States. This shift is responsible for the trend toward a heavier crude supply mix on the international market. Transportation fuels and petrochemical feedstocks are in increasing demand; hence many refiners would like to get out of the fuel oil business, More “bottom-of-the-barrel” conversion capability will be required in many refineries to efficiently process these heavier feedstocks and maximize production of light products.

ISSN:0161-4940    

DOI:10.1080/01614948408064720

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Since worldwide conversion processes are used to upgrade heavy oil to distillates, the hydrotreatment of light gas oil (LGO) as a downstream process has been used more extensively. This fraction (LGO) is produced from thermal or catalytic cracking or hydrocracking processes. It contains high amounts of unsaturates, nitrogen, and sulfur compounds which cause instability while in storage due to gum formation. The use of LGO as a fuel oil for diesel engines plugs the filter and produces sulfur and nitrogen emissions. These sulfur and nitrogen compounds arise from the cracking of heavy cuts and are aromatic-type molecules which are difficult to hydrogenate. This cut also possesses a low cetane index (CI) which must be increased (by aromatic hydrogenation) because of its poor motor performance. Color and color stability are associated with a high bromine number (BN, unsaturated content), nitrogen, and aromatic content. In order to improve these properties, a deep hydrogenation is sometimes required.

ISSN:0161-4940    

DOI:10.1080/01614948408064721

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

An overview of the history and development of molecular sieve materials since their discovery and commercialization is presented. The evolutionary changes in their composition, sorptive and catalytic properties, surface selectivity, and stability characteristics are emphasized.

ISSN:0161-4940    

DOI:10.1080/01614948408064722

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

There have been many studies in the last 30 years on hydrotreating catalysts. The early studies involve various metals and supports and their influence on activity. Later studies have applied bulk and surface analytical techniques to defining the structure of catalysts and to activity [1–4]. Few of the papers try to correlate the bulk and surface properties to the preparation method for a fixed composition, and the resulting performance observed [5].

ISSN:0161-4940    

DOI:10.1080/01614948408064723

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The catalytic control of automobile exhaust pollutants (hydrocarbons, carbon monoxide, nitrogen oxides) is now a common practice in the United States and Japan, and there are strong indications that the technology may be introduced in other parts of the world in the coming years. The simultaneous conversion of all three of the above pollutants is achieved by the near-stoichiometric operation of noble metal catalysts which are supported either on alumina particles or on alumina-washcoated cordierite monoliths, A summary of the developments which lead to this technology can be found, e. g., in Hegedus and Gumbleton [1] and references therein.

ISSN:0161-4940    

DOI:10.1080/01614948408064724

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor